Method for making plastic articles



Sept. 22, 1964 w. z. SALCER 3,150,215

METHOD FOR MAKING PLASTIC ARTICLES Filed March 25, 1963 4 Sheets-Sheet 1 A TTORNEY Sept. 22, 1964 w. z. SALCER 3,150,216

METHOD FOR MAKING PLASTIC ARTICLES Filed March 25, 1965 4 Sheets-Sheet 2 H 37 Jfw Jo" 42 INVENTOR.

i7 5 q s w .A TJ'ORNEY Sept. 22, 1964 w z, SALCER 3,150,216

METHOD FOR MAKING PLASTIC ARTICLES Filed March 25, 1963 4 Sheets-Sheet 3 INVENTOR. W/ZL/A/V Z. JALCER 4 BY zaw saw flwp ATTORNEY Sept. 22, 1964 w. z. SALCER 3,150,216

METHOD FOR MAKING PLASTIC ARTICLES Filed March 25, 1963 4 Sheets-Sheet 4 United States Patent 3,lltl,2lo lfllliflltl lll MAKll lG PLASTHQ Als'llCllEl William 25. Salter, llego Park, New York, NY, assignor to ll. @s S. Plastic Art, lnc, Jersey City, NJ at corpora tion of New .l'erse h lar. 25, i963, Ser. No. 267,755 8 (Ilainis. (Cl. 264-l5ll This invention relates to a method of manufacturing flexible sheet like articles having a raised bead pattern on one surface thereof. More particularly, it relates to a method of manufacture, from plastic materials, of such articles as tablecloths, place mats, doilies, shower curtains, drapes, aprons and the like comprised of a perforated lace like, three dimensional plastic pattern bonded to a backing sheet of flexible plastic material or to a layer of plastic loam or to both. The plastic materials with which this invention may be useful include soft rubbers as well as a variety of flexible thermoplastic and thermosetting materials.

Small place mats having a perforated lace like raised pattern bonded to a backing sheet of contrasting color are believed to be presently on the market. But where, as in many lace patterned articles, it is desired to provide article having irregular or scalloped edges on a large article, serious problems have heretofore been encountered in the economical manufacture of such articles. These problems have particularly resulted from conforming the edges of the backing sheet or layer to the indentations of the edges of the lace like pattern.

Accordingly, it is an object of the present invention to provide a new and improved economical method of manufacturing articles of the character described herein.

It is another object of this invention to provide a novel method of manufacturing flexible, sheet like articles comprised of a lace like three dimensional pattern bonded to a backing sheet or layer of contrasting color, all from plastic materials, particularly where said pattern has irregular or indented edges and it is desired to conform the edges of said backing sheet or layer to the edges of said pattern.

For a better understanding of the present invention together with other and further objects thereof, reference is had to the following description, taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

In the drawings:

PEG. 1 is a diagrammatic representation of apparatus suited to the practice of the method of manufacture of this invention.

MG. 2 is a top plan view of the mold or die suited to the practice or" this invention showing the edges of the die pattern engraved thereon and showing, in a fragmentary manner and schematically the die pattern engraved within said edges.

H6. 3 is a sectional View of a portion of said die taken on line 33 of FIG. 2.

HQ. 4 is a sectional view similar to FIG. 3, but showing both the pattern material and the backing material applied to the die.

HS. 5 is a schematic view of a mold stripping step of the method of this invention.

PEG. 6 is a plan view of the intermediate article of manufacture resulting from the practice of this invention showing the edges of the intermediate pattern thereon and a fragmentary, schematic representation of the huished pattern within said edges.

PEG. 7 is a sectional View of a portion of said inter mediate article taken along line '7-7 of FIG. 6.

FIG. 8 is a schematic fragmentary representation of the step of the inventive method which results in separating unwanted backing material from the finished article.

FlG. 9 is a plan view of the finished article showing a fragmentary, schematic representation of the finished pattern thereon.

FlG. 10 is a sectional view on line lit-ill of Eli 9.

FIG. ii is a photograph of a pattern only showing a type of finished bead pattern in connection with he manfacture of which the instant invention is useful.

Referring now to the drawings wherein like reference numerals denote corresponding elements throughout the several views, and particularly to FIG. 1, in the practice of applicants method, a succession of plate type dies ll), each similar to that shown in FIG. 2, are fed from a loading station ll onto a moving endless conveyor means $12, each of the dies lid being positioned on said conveyor means 12 with its surface 13 hearing the engraved die pattern l4 uppermost.

Passing along the conveyor means 12 the uppermost surface T13 of each successive die Jill is coated with a first or pattern layer of plastic material by the reverse roll coater lit to which said plastic material is continuously supplied from a suitable reservoir 17. While, as explained elsewhere herein, my invention would be useful in the manufacture of articles from a variety of plastic materials, a vinyl dispersion plastisol has been found well suited as a raw material in the practice of the invention. This first layer of plastic material 15 completely fills the die pattern 14 on the dies ill with excess material deposited on the upper surfaces 13 of said dies ll.

The coated dies in next are moved progressively beneath a series (five are shown here for purposes of illustration) of doctor blades 19 which gradually wipe the excess plastic material of the first layer from the upper surface 13 of each die ll As each die it) leaves the downstream doctor blade 19a, its upper surface 13 has been wiped clean of excess material leaving only the die pattern lid completely tilled with the plastisol.

Next, each die llll is successively passed beneath a means 2t} for applying a backing layer of plastic material to the upper surface 13 of said die iii. For illustrative purposes said means 2t) has been shown in FIG. 1 as a transversely reciprocating spray nozzle 21 fed by flexible hoses T12 and 23 with air and plastisol respectively. By means of the transversely reciprocating motion of the nozzle El along the guides 24-, a uniform second layer of plastic material is applied to the entire upper surface 15 of each die All. It should be appreciated that various alternative means could be used for applying the second or backing layer to the dies Elli, said alternative means including a stationary spray system, a roll. coater or even lamination before curing or after a partial cure, it being essential only that the second layer material be compatible with the first layer material in the die pattern 14 so that it may be completely bonded therewith. Most desirable decorative eilects are obtained when the second layer is clear or of a color contrasting with the color of the first or pattern layer.

Next, each die ill, bearing both layers of plastic material, is conveyed through a tunnel type oven 26 where the plastic material is cured in and on the dies fill. Wtih the vinyl plastisol used by me for both layers, a curing time of seconds at 390 F. has been found to be desirable under normal conditions.

As the dies ill bearing the semi-finished plastic articles 32 emerge from the oven 26 they may be cooled by various means including fans, water sprays arid/or water im mersion. For illustrative purposes, in FIG. 1 the dies are shown to be cooled by successively immersing them in a tank 29 of water. After cooling, the dies ill may be removed from the conveyor means 112 to a strip ping station 3d where the semi-finished article 32 may be stripped manually from the die it? as shown in 1316. 5. After the dies it) have been stripped they may be washed and returned, by other conveying means, to the loading station 11, the entire process heretofore described being continuously and automatically performed except for the manual die stripping step.

It will be useful at this point to consider the detailed structure of the mold or die and of the semi-finished article 32 stripped therefrom before continuing with a description of the final method step of this invention. Referring, then, particularly to FIGS. 2, 3 and 11, in FIG. 11 is shown a photographic reproduction of a portion of a typical finished pattern 14b corresponding to the first layer or my finished article 45, in this case a place mat. It will be observed that the pattern Mb exhibits a truly lace like appearance in that, as in a textile lace or piece of open crocheted work, the individual yarns or stitches are visibly reproduced. It will be further observed that the outer edge 34 of the border 33 of said finished pattern 14b is defined by a continuous bead simulating a continuous strand of chain stitching or the like which follows a series of intricate indentations around the periphery of the border 33. it is to such a series of border indentations that it is generally desired to have the second or backing sheet or layer of the article 45 conform.

To achieve this end a plurality of dies 10, an example of which is shown schematically in FIGS. 2 and 3, are manufactured from flat plates of metal 35, preferably of magnesium. A %;2 inch thick plate having a surface area sufiicient to accommodate the die pattern 14 with a rnargin of 2 to 3 inches between the edges of the die pattern 14 and the plate 35 has been found satisfactory as a die blank. On one surface of this plate 35, the entire die pattern 14 is photographically engraved by methods well known in the art thereby producing the die pattern 14- as an interconnected pattern of grooves or depressions 36 in the surface of the plate 35. For reasons further explained hereinafter it may in some cases be desirable to exaggerate slightly the depth of the groove 36a corresponding to the outer edge of the finished pattern 14b to appear on the finished article 45, although this will not always be necessary.

In the practice of the instant invention an additional continuous groove 37 not corresponding to any portion of the finished pattern 14b intended to appear on the finished article 45 is provided, as part of the die pattern 14, in the surface 13 of the die 10 external to and closely spaced from the outer edge groove 36a of that portion of the die pattern 14 corresponding to the finished pattern 14b on the finished article 45. This additional groove 37 closely follows each indentation of the outer edge groove 36a of the desired finished pattern 14b and will usually be of substantially the same cross-section. The outer groove 37 of the die pattern 14 may be formed by machining the photoengraved die It) or by photoengraving from. the original art work with an additional border line added.

It will be appreciated that the optimum depths of the grooves 36a and 37 as well as the optimum spacing therebetween depends upon a number of variables including the thickness of the backing layer or layers and such physical properties of the materials of the pattern layer and backing layer as tensile strength and elongation. With the vinyl plastisols employed by me for both the pattern and the backing sheet it has been found, for example, that a table cloth having a backing layer of .005" thickness may be satisfactorily made using a die 10 provided with grooves 36a and 37 each having a cross-sectional depth of from .040" to .050 and a cross-sectional width of from .040 to .050".

Referring now to FIGS. 4, 5, 6 and 7 and initially to FIG. 4, the intermediate article of manufacture 32 which results in the practice of this invention will be described.

In FIG. 4 is shown a die 10, the die pattern 14- of which is completely filled with the first layer 40 of plastisol, the excess plastisol having been wiped clean from the upper surface 13 of the die 10. The second or backing layer 41 of plastisol, preferably of a contrasting color, has been applied to the upper surface 13 of the die It) completely covering the first layer 40 and extending therebeyond to produce a sheet of excess plastic backing material or flash 41a overlying the outermost groove 37 and surrounding the pattern 14.

After the pattern layer 4d and the backing layer 41 have been cured and cooled on the die in and have been hand stripped from the die 19 as shown in FIG. 5, the resultant prdouct is the intermediate article of manufacture 32 shown in FIGS. 6 and 7. This intermediate article 32 comprises, in a cured state, the backing sheet 41 of plastic material on one surface of which is superimposed and fused thereto the desired intermediate pattern 14a of beads or ridges of the pattern layer 40 preferably of a contrasting color. The intermediate pattern 14a includes the desired finished pattern 14b, the outer edges of said finished pattern 14b being comprised of a continuous edge head or pattern head 42 of said pattern layer 40 completely enclosing said finished pattern 14b and connected to various interior beads thereof to form a part of said finished pattern 14!). Also superimposed on said backing sheet if as part of the intermediate pattern 14 is a continuous flash bead 43 of said pattern layer 40 positioned in closely spaced relationship exterior to said edge head 42 of said finished pattern 14b and completely surrounding the same. The dimensions of the edge head 42 and the flash head 43 as Well as the space between them will, of course, approximate the corresponding dimensions of the grooves 36:: and 37 in the die 10. The unwanted side scrap or fiash 41a extends from the interior edge of the fiash head 53 to the edges of the backing sheet 41.

The final inventive method step of the instant invention is shown in FIG. 8. In this step the edge head 43 may be broken or cut at an appropriate point or folded and said edge head 43 together with the fiash 41a is then manually torn from the finished article 45 to complete the manufacturing process and provide a finished article 4-5 wherein the edges of the backing layer 41 conform closely to the edge head 42 of the finished pattern 14b. It should be appreciated that, while a preferred sequence of method steps has been described, the steps shown in FIGS. 5 and 8 could be reversed in that the flash 41a and flash head 43 could, under appropriate circumstances, he ripped from the finished article 45 while the intermediate article 32 is still in the mold 10. The finished article of manufacture, a place mat 45, is shown schematically in FIGS. 9 and 10.

It will be appreciated that a variety of apparatus generally equivalent to that shown diagrammatically in FIG. 1 could be used in the practice of my method, this invention being unrelated to the specific apparatus illustrated except to the mold or die employed. For instance, other apparatus could be used for applying one or both layers of plastisol or different cooling apparatus could be used. Also, it should be appreciated that the expression plate as used herein with reference to the molds or dies includes curved plates as well as flat plates and even a cylinder wall provided with mold cavities.

Further, only the basic method has been described herein. Without departing from the spirit of this invention additional layers or laminations could be applied on top of the second or backing layer, curing could be performed between plastisol applications, or the mold stripping and flash stripping steps could be reversed or combined. Also, this invention would be useful in forming interior openings in articles of the character described as well as for stripping unwanted edge scrap from the desired finished article.

From the foregoing, it is believed that the method and apparatus for practicing the instant invention as well as the intermediate article of manufacture thereof will be readily comprehended by persons skilled in the art. It is to be clearly understood, however, that various changes in the apparatus herewith shown and described and in the method of practicing the invention outlined above may be resorted to Without departing from the spirit of the invention as defined by the appended claims.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. In a method of manufacturing finished articles of flexible plastic material, the steps comprising: forming a sheet of plastic material of substantially uniform thickness; forming at least one pair of closely spaced continuous beads of plastic material; said sheet and said beads being placed in overlying contact with each other while at least one thereof is still less than fully cured; curing said still less than fully cured material While simultaneously bonding said sheet and said beads together to form a cured flexible plastic sheet having bonded to one surface thereof at least one pair of closely spaced continuous beads of flexible plastic material demarcating said desired finished article from the unwanted scrap material com.- prising the rest of said sheet; and separating said scrap material from said finished article by tearing said sheet between said beads.

2. In a method of manufacturing articles of flexible plastic material, the steps comprising: forming, from fluid plastic material, a pattern layer comprised of a pair of closely spaced continuous beads including a pattern bead and a flash bead; forming, from fluid plastic material, a backing layer comprised of a plastic sheet of substantially uniform thickness and larger than the area circumferentially enclosed by said beads; one of said layers being formed in overlying contact with the other while at least one of said layers is still less than fully cured, fully curing said still less than fully cured layer while simultaneously bonding said layers together to form a cured flexile plastic sheet having bonded to one surface thereof a continuous pattern bead of flexible plastic material completely enclosing a desired finished pattern and forming the outer edge thereof and a continuous flash bead completely surrounding said pattern bead and closely spaced with respect thereto, said flash bead demarcating said finished pattern from the unwanted flash comprising the area of said sheet outside said finished pattern; and tearing said flash bead and said flash from the finished pattern portion of said bonded composite sheet by pulling said flash and said flash bead from said finished pattern portion of said sheet.

3. In a method of manufacturing finished articles of flexible plastic material using a mold provided on one surface thereof with a pattern of grooves including at least one pair of closely spaced continuous grooves demarcating the part of said mold surface corresponding to the desired finished article from the rest of said mold surface, the steps comprising: filling said groove pattern only with a first layer of fluid plastic material; depositing at least one backing layer of plastic material on said mold surface to cover and extend beyond said pattern; curing said material in and on said mold; thereby forming a cured flexible plastic sheet having bonded to one surface thereof at least one pair of closely spaced continuous beads of flexible plastic material demarcating said desired finished article from the unwanted scrap material comprising the rest of said sheet; and separating said scrap material from said finished article by tearing said sheet between said closely spaced heads.

4. In a method of manufacturing finished articles of flexible plastic material, the steps comprising: depositing, upon a mold provided on one surface thereof with a pattern of grooves including at least one pair of closely spaced continuous grooves demarcating the part of said mold surface corresponding to the desired finished article from the rest of said mold surface, a first layer of fluid plastic material; removing said first layer of plastic material from said mold surface except for the plastic material contained in said groove pattern; depositing at least one backing layer of plastic material on said mold surface to cover and extend beyond said pattern; curing said material in and on said mold; to form a cured flexible plastic sheet having bonded to one surface thereof at least one pair of closely spaced continuous beads of flexible plastic material demarcating said desired finished article from the unwanted scrap material comprising the rest of said sheet; and separating said scrap material from said finished article by tearing said sheet between said beads.

5. In a method of manufacturing finished articles of flexible plastic material utilizing a plate type mold provided on one surface thereof with a pattern of grooves including at least one pair of closely spaced continuous grooves demarcating the part of said mold surface corresponding to the desired finished article from the rest of said mold surface, the steps comprising: filling said groove pattern only with a first layer of fluid plastic material; depositing, prior to any application of heat to said first layer, a second layer of fluid plastic material of substantially uniform thickness on said mold surface to cover and extend beyond said first layer; applying heat to cure both layers simultaneously in and on said mold to form a cured flexible plastic sheet having bonded to one surface thereof at least one pair of closely spaced continuous beads of flexible plastic material demarcating said desired finished article from the unwanted scrap material comprising the rest of said sheet; and separating said finished article from said sheet by tearing said sheet between said closely spaced heads.

6. In a method of manufacturing finished articles of flexible plastic material, the steps comprising: depositing upon a mold provided on one surface thereof with a pattern of grooves including at least one pair of closely spaced continuous grooves demarcating the part of said mold surface corresponding to the desired finished article from the rest of said mold surface, a first layer of fluid plastic material; removing said first layer of plastic matcrial from said mold surface except for the plastic material contained in said groove pattern; depositing, prior to any curing of said first layer, at least one backing layer of fluid plastic material on said mold surface to cover and extend beyond said pattern; curing said material in and on said mold; to form a cured flexible plastic sheet having bonded to one surface thereof at least one pair of closely spaced continuous beads of flexible plastic material dcmarcating said desired finished article from the unwanted scrap material comprising the rest of said sheet; and separating said scrap material from said finished article by tearing said sheet between said closely spaced beads.

7. The method of claim 6, wherein only one said backing layer is applied by spraying.

8. In a method of manufacturing finished articles of flexible plastic material, the steps comprising: depositing, upon a mold provided on one surface thereof with a pattern of grooves including at least one pair of closely spaced continuous grooves demarcating the part of said mold surface corresponding to a desired finished article from the rest of said mold surface, a first layer of fluid plastic material; removing said first layer of plastic material from said mold surface except for the plastic material contained in said groove pattern; depositing, prior to any curing of said first layer, at least one backing layer of fluid plastic material on said mold surface to cover and extend beyond said pattern; curing said material in and on said mold; thereby forming a cured flexible plastic sheet having bonded to one surface thereof at least one pair of closely spaced continuous beads of flexible plastic material demarcating each desired finished article from the unwanted scrap material comprising the rest of said sheet; cooling said cured sheet; and separating aid scrap material from each said finished article by tearing said sheet between said closely spaced beads.

References (314011 by the Examiner UNITED STATES PATENTS Beyer 264-325 Latulip 1844 Falk 1 8-44 Wieland 264-161 Griffith 264-325 Parkhurst 264161 Gammeter 18-41 Purinton et a1. 264161 Markus et a1. 156-267 Adams 264-45 References Cited by the Applicant UNITED STATES PATENTS Ratiginer et 01. Miller et al. Diller et a1. Brueggeman. Spanel. Kraszeski.

15 ALEXANDER H. BRODMERKEL, Primary Examiner.

DOUGLAS 1. DRUMMOND, Examiner. 

1. IN A METHOD OF MANUFACTURING FINISHED ARTICLES OF FLEXIBLE PLASTIC MATERIAL, THE STEPS COMPRISING: FORMING A SHEET OF PLASTIC MATERIAL OF SUBSTANTIALLY UNIFORM THICKNESS; FORMING AT LEAST ONE PAIR OF CLOSELY SPACED CONTINUOUS BEADS OF PLASTIC MATERIAL; SAID SHEET AND SAID BEADS BEING PLACED IN OVERLYING CONTACT WITH EACH OTHER WHILE AT LEAST ONE THEREOF IS STILL LESS THAN FULLY CURED; CURING SAID STILL LESS THAN FULLY CURED MATERIAL WHILE SIMULTANEOUSLY BONDING SAID SHEET AND SAID BEADS TOGETHER TO FORM A 